1. Field of the Invention
This invention relates to a mastering apparatus suitably applied for production of master disks for a compact disk and a minidisk.
2. Description of the Related Art
A so-called minidisk (optical disk) (MD) for reproducing or recording and reproducing an audio signal has been developed. The minidisk has a smaller diameter than the diameter of a compact disk (CD) which can reproduce an audio signal without deterioration of the sound quality.
While the minidisk has a very small diameter of 64 mm, it requires the same recording time as the compact disk by making use of a special signal compression processing technique. The signal format of the minidisk is approximately the same as the CD-ROM mode 2.
When a master disk for a compact disk is to be manufactured, a compact disk master tape is first produced in a studio. A compact disk format signal is then produced, based on the compact disk master tape, using a compact disk mastering apparatus installed in a compact disk producing factory. The compact disk format signal is sent to a disk cutting apparatus, by which a master tape for a compact disk is produced.
When a master disk for a minidisk is to be produced, similar, but separate, equipment as that used to make a master disk for a compact disk is used. Consequently, a mastering apparatus for production of a master disk for a compact disk and another mastering apparatus for production of a master disk for a minidisk must be provided separately in a disk producing factory.
However, since the signal format used to make a minidisk is approximately the same as that used to make a CD-ROM (compact disk read only memory) as described above, most of the component elements of a compact disk mastering apparatus in a studio and a compact disk mastering apparatus in a factory can be utilized as component elements for production of a minidisk. If the mastering apparatus for a compact disk and a minidisk can be constructed as a single apparatus, then the compact disk producing factory can also be utilized as a minidisk producing factory, and consequently, investment in a new plant and new equipment can be saved. Additionally, discovery of a piracy, discovery of production of a minidisk without obtaining a right of authorship will be facilitated.